She replied: “One man’s positive can be another man’s negative. One of the surprises may be to see people with certain beliefs as people who can be treated.

“Someone who has for example become radicalised to a cult ideology – we might stop seeing that as a personal choice that they have chosen as a result of pure free will and may start treating it as some kind of mental disturbance.

“In many ways it could be a very positive thing because there are no doubt beliefs in our society that do a heck of a lot of damage.

“I am not just talking about the obvious candidates like radical Islam or some of the more extreme cults. I am talking about things like the belief that it is OK to beat your children.

But she concedes motives beyond those which are purely clinical run into problematic territory.

Writing in September, a month before the release of her book The Brain Supremacy, she says: “The ethics developed by doctors, over centuries, to deal with human suffering, are different from those developed by scientists trying to understand how the world works.

“They're still more different from the ethics of businesses keen to cash in on the new technologies… techniques created to heal can also be employed for other purposes, and the ability to get data from living brains is a holy grail for many interested parties other than neuroscientists and doctors.”

She adds: “Human systems are always changed by their interactions with others, and in hard-to-calculate ways. What a volunteer says and does in a research lab may be altered not only by the lab environment or the phrasing of a question, but by who the experimenters are and how they behave. The human person thus needs to be considered. Technologies which directly scan or manipulate brains cannot be neutral tools, as open to commercial exploitation as any new gadget.”

Links between extreme faiths and mental health have been made before, with former president of the Royal College of Psychiatrists Dr Dinesh Bhugra, highlighting recent religious conversions being more associated with a developing psychotic mental illness.